1. Field of the Invention
The present invention relates to a method for manufacturing a support frame of a display panel being used as a display device for personal computers, TV (television) sets, or a like; and more particularly to the method of manufacturing the support frame of the rectangular display panel which is used to support a portion surrounding the rectangular display panel and to the support frame of the rectangular display panel manufactured by the above method and to the display device equipped with the above support frame.
The present application claims priority of Japanese Patent Application No. 2001-088848 filed on Mar. 26, 2001, which is hereby incorporated by reference.
2. Description of the Related Art
As a rectangular display panel, an LCD (Liquid Crystal Display) panel, a PDP (Plasma Display Panel), or panels made up of light emitting elements such as an EL (Electroluminescence), an LED (Light Emitting Diode), a VFD (Vacuum Fluorescent Display), or a like are conventionally available. In the LCD panel, a region surrounded by a scanning electrode mounted in a row direction and by a data electrode mounted in a column direction is used as a pixel, and by feeding a data signal produced from an image signal to a data electrode and by feeding a scanning signal produced from a synchronous signal to the scanning electrode, a character or an image is displayed on a display screen. Also, in the LCD panel, a data electrode driving circuit adapted to generate the above data signal and a scanning electrode driving circuit adapted to generate the above scanning signal, together with control circuits used to control these circuits, gray-scale power source, or a like, are formed integrally as an LCD module. As shown in FIG. 29, in an LCD module 1, a front of a portion surrounding the LCD module 1 is supported by an approximately rectangular-shaped front frame 2 and a rear of the portion surrounding the LCD module 1 is supported by an approximately rectangular-shaped center frame 3.
In the LCD module 1 shown in FIG. 29, the control circuits, gray-scale power source, or a like are mounted on a printed board 4, while the data electrode driving circuit made up of semiconductor circuits (ICs) is mounted on a film carrier tape electrically connecting the printed board 4 and an LCD panel 5 by each of a plurality of corresponding data electrodes and is packaged as TCPs (Tape Carrier Packages) 61 to 68. The printed board 4 is attached to an upper frame 3a of the center frame 3. Moreover, positioning members 7 (another positioning member 7 in a lower right portion is not shown) shown in FIG. 29 is used to correctly attach the LCD module 1 in a specified position of the center frame 3. In the positioning member 7 made of a resin, as shown in FIG. 30, two rectangular parallel-piped bodies 9 are formed integrally on an upper face of an approximately L-shaped substrate 8 in such a manner that axial lines of the two rectangular parallel-piped bodies 9 intersect each other at right angles and, in the vicinity of the two rectangular parallel-piped bodies 9, one circular hole 10 is formed. The positioning member 7 is fixed at the center frame 3 in a method as described below. That is, first, each of the two rectangular parallel-piped bodies 9 of the positioning member 7 is inserted, from a rear side of the center frame 3, into a larger size inserting hole 11 than each of upper areas of the two rectangular parallel-piped bodies 9 each being formed in four corners of the center frame 3. Then, a thread (not shown) is fitted, with some tolerance being allowed, into the circular hole 10 from a rear side of the L-shaped substrate 8 and is inserted fitly into a thread hole 12 formed in the vicinity of the inserting hole 11 of the center frame 3 to fix the positioning member 7 to the center frame 3.
The front frame 2 and the center frame 3 are conventionally manufactured by following methods. Hereinafter, the front frame 2 and center frame 3 are collectively called a “support frame”. That is, after a pair of L-shaped component members is assembled in combination so that a rectangular structure is formed and both end edges of the pair of the L-shaped component members are melted and bonded to each other to form a rectangular frame plate member, the frame plate member is bent in a manner that the rectangular frame plate has an approximately L-shaped cross section, and the bent frame plate is used as the support frame. A manufacturing method of this type is disclosed in Japanese Patent Application Laid-open Nos. Hei 4-73714 and 2000-39850. Hereinafter, technology disclosed in these Patent Applications is called a “first conventional example”.
Moreover, in a Japanese Patent Application Laid-open No. 2000-314872, another technology is disclosed. That is, in the example, as shown in FIG. 31, a rectangular-shaped center frame 13 is assembled so as to have an approximately rectangular-shaped configuration which is made up of two approximately L-shaped component members 13a and 13b and end portions of each of the L-shaped component members 13a and 13b are placed at corners of the rectangular-shaped center frame 13 being diagonally opposite to each other. Moreover, as shown in FIGS. 32A and 32B, a fitting/coupling section 14 made up of plane pierce-shaped convex portions 14a and plane pierce-shaped concave portions 14b is provided at a place where the L-shaped component member 13a is to be coupled to the L-shaped component member 13b and another fitting/coupling section 15 with plane pierce-shaped convex portions 15a and plane pierce-shaped concave portions 15b is provided at a place where the L-shaped component member 13a is also to be coupled to the L-shaped component member 13b. In the L-shaped component members 13a and 13b, portions being extruded from a side line of each of the L-shaped component members 13a and 13b or being partitioned by dotted lines in side portions of each of the L-shaped component members 13a and 13b are bending margins 13c to be used when the L-shaped component members 13a and 13b are bent so as to be approximately L-shaped in cross sections.
A constricted portion 14c is formed in each of the plane pierce-shaped convex portions 14a and a constricted portion 15c is formed in each of the plane pierce-shaped convex portions 15a and the constricted portion 14c is formed in each of the plane pierce-shaped concave portions 14b and the constricted portion 15c in each of the plane pierce-shaped concave portions 15b. Therefore, this causes the plane pierce-shaped convex portions 14a and the plane pierce-shaped concave portions 15a to be tightly fitted each other, thus preventing them from being separated from each other in a horizontal direction. In the plane pierce-shaped convex portions 14a and 15a are formed boss portions 14d and 15d respectively in a half-punched state by a press working method.
Next, a method for manufacturing the center frame 13 is explained. First, the fitting/coupling sections 14 and 15 in each of the L-shaped component members 13a and 13b are positioned to be fitted from upward and downward directions to cause the plane pierced-shaped convex portions 14a and 15a to be mechanically fitted into the plane pierced-shaped concave portions 14b and 15b. Next, when the fitting/coupling sections 14 and 15 are crimped from upward and downward directions by using a pressing machine, each of the boss portions 14d and 15d is plastic-deformed and expanded, which causes the plane pierce-shaped convex portions 14a and 15a and the plane pierce-shaped concave portions 14b and 15b to be fitted more tightly and to be integrated. Then, by bending the bending margins 13c of each side using the pressing machine, the rectangular-shaped center frame 13 having approximately the same shape as the rectangular-shaped center frame 3 shown in FIG. 29 is manufactured. Hereinafter, this technology is called a “second conventional example”.
However, the first conventional example has a disadvantage in that, since the melting and bonding processes are included in the method of manufacturing the support frame for the display panel provided in the first conventional example, generally, long working hours are required. Another problem is that, when a laser deposition method is used for the melting and bonding processes, in particular, additional special equipment has to be prepared.
On the other hand, the method for manufacturing the support frame for the display panel provided in the second conventional example also has a disadvantage in that, since the formation of the constricted portions 14c and 15c is necessary, if hardness of the employed component member is very high, it is difficult to form such the constricted portions 14c and 15c precisely. Thus, the constricted portions 14c and 15c cause low strength of the support frame itself. As a result, if the constricted portions 14c and 15c have not been precisely formed, when the plane pierce-shaped convex portions 14a and 15a and the plane pierce-shaped concave portions 14b and 15b are mechanically fitted, there is a danger that the fitting/coupling sections 14 and 15 would not be fitted completely. Moreover, depending on conditions applied when the plane pierce-shaped convex portions 14a and 15a and the plane pierce-shaped concave portions 14b and 15b are mechanically fitted, a case may occur in which both the plane pierce-shaped convex portions 14a and 15a and plane pierce-shaped concave portions 14b and 15b or either of the plane pierce-shaped convex portions 14a and 15a or plane pierce-shaped concave portions 14b and 15b are broken in the constricted portions 14c and 15c. This means that, in the second conventional example, types of component members or manufacturing conditions that can be applied are limited and, if types of the component members are erroneously selected or the manufacturing conditions are erroneously set, defectives continuously occur and a yield is decreased, as a result. Furthermore, in the case of the second conventional example, after the plane pierce-shaped convex portions 14a and 15a and the plane pierce-shaped concave portions 14b and 15b are mechanically fitted, process of crimping the fitting/coupling sections 14 and 15 from upward and downward directions using the pressing machine is needed, which causes low productivity in manufacturing the support frame.
Furthermore, in an upper portion of the above LCD module 1, as shown in FIG. 29, a plurality of ICs making up the data electrode driving circuit is mounted on a film carrier tape which is packaged in a form of the TCPs 61 to 68. Since the plurality of ICs generates data signals to be fed to the data electrode in the LCD panel 5, high frequency noises of about several kHz to 1 GHz occur and, therefore, unless an electromagnetic shielding unit is provided, the noises cause an EMI (Electro Magnetic Interference) to other electronic devices. To solve this problem, it can be thought that, as a material for the front frame 2, iron or aluminum having high conductivity is used to have it serve also as an electromagnetic shielding unit. However, iron has a high specific gravity and high hardness and, therefore, when it is used for a large screen, a weight of a display device becomes high and iron is difficult to be processed. Aluminum has also a disadvantage because it is expensive. As a material for the front frame 2, conventionally, stainless steel is used which has low conductivity but small specific gravity and low hardness and, in a portion above the data electrode driving circuit, a copper foil having high conductivity is pasted up. Therefore, a process of pasting up the copper foil is additionally required which causes an increase in component counts and in the number of processes.
As shown in FIG. 33, in a lower portion of an upper frame section 2a of the front frame 2 are mounted the printed board 4, TCPs 61 to 68, or a like, while the upper frame section 2a of the front frame 2 is used as a terminal being of a ground level. Therefore, in the conventional support frame, in order to prevent the printed board 4, TCPs 61 to 68, or a like from being in contact with the upper frame section 2a of the front frame 2, an insulator 16 such as silicon rubber or a like is pasted up on a lower face of the upper frame section 2a of the front frame 2 to ensure insulation between the upper frame 2a of the front frame 2 and the TCPs 61 to 68. As a result, a process of pasting up the insulator 16 is additionally required which causes an increase in component counts and in the number of processes.
Moreover, in the conventional support frame, in order to attach the LCD module 1 exactly to a specified position in the center frame 3, the positioning member 7 is used. Therefore, a process of mounting the positioning member 7 is additionally required which also causes an increase in component counts and in the number of processes. Such the inconvenience as in the LCD also occurs more or less in the display panel such as PDP or panels made up of light emitting elements such as the EL, LED, VFD or a like in an approximately same manner.